Once upon a time: Fired from every research job he’s ever had, shy scientist Sidney Stratton ends up as a worker at a cotton mill — where, mistaken for a staff chemist, he takes over a small lab and invents a cloth that never gets dirty and never wears out. Wonderful news for consumers — not so wonderful for the big clothing companies that, in a rare but firm alliance between capital and labor, join with their workers to destroy the formula and shut Sidney up. But he has a secret weapon — heiress Daphne Birnley, who thinks he’s rather fascinating, actually.

Inappropriate material: Not a smidgen.

Why kids will like it: Children are born inventors and Sidney’s experiment is incredible fun (there are lots of bubbling test tubes and an explosion or two). And the movie uses the deadpan Alec Guinness for great Keatonesque slapstick, including a funny assault on the locked mansion of the cotton mill’s owner and an escape from a tiny apartment where Sidney’s foes try to stash him.

Why adults will like it: For about a decade, Ealing Studios was the premier producer of wry British comedies, with Guinness starring in several — and this is one of the best (along with the wonderful "The Lavender Hill Mob," made the same year). And the superb cast includes Joan Greenwood — owner of the sexiest voice in English movies — as Daphne, and fine character actors such as Michael Gough, Miles Malleson and the venerable Ernest Thesiger (who horror fans will remember as Dr. Pretorious in "The Bride of Frankenstein").

Fast forward/freeze frame: American children may need a bit of help with some of the accents (and may have trouble grasping the formidable power of pre-Thatcher labor unions).

Fun trivia: The glub-bubble-glub of Sidney’s experiments was later set to music and released as the "The White Suit Samba." And that magical stunt of Guinness walking down the side of the Birnley mansion? Actually done by the star himself, holding on to a strand of piano wire. (The prop man swore it was perfectly safe; in fact, the wire snapped just as Guinness was about to reach the ground.)

Teachable moments: The entire plot of the movie turns on a simple point: What may seem like a wonderful invention can have unintended consequences. That opens up a lot of interesting discussions about the history of science, as well as sci-fi stories about experiments with disappointing outcomes; middle-school readers would definitely enjoy Daniel Keyes’ "Flowers for Algernon."

Double features: "The Lavender Hill Mob," with Guinness as an unlikely bank robber, is an obvious follow-up. And slightly older children will appreciate Mackendrick’s and Guinness’ reteaming on the pitch-black comedy "The Ladykillers."